Control for furnaces



Dec. 14 1926.

E. MQLEAN CONTROL FOR FURNACES Filed Sept. 10, 1923 3 Sheets-Sheat 1 INVENTOR.

A TTORNEYS 4 W1 TNESS:

Dec. 14 1926.

E. MCLEAN CONTROL Eon FURNACES Filed Sept. 10, 1923 3 Sheets-S at 3 INVENTOR.

4b -ATTORNEYS I ca Patented Dec. 14, 1926.

I UNITED STATES PATENT OFFICE.

EMBURY MOLEAN, 0F BROOKLYN, NEW YORK, ASSIGNOR TO THE ENGINEER COM- IPANY, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

CONTROL FOR FURNACES.

Application filed September 10, 1923. Serial No. 681,780.

the control for a furnace to which fluid fue is supplied.

My invention will best be understood by reference to the accompanying drawin 's in which I have illustrated thepreferred orm of apparatus for carrying out my invention, and in which Fig. 1 is a diagrammatic side view, partia ly in section, of a boiler and its furnace, together with the control therefor; Fig. 2 is an enlarged side view of certain parts shown in Fig. 1 and partially in section to illustrate a valve structure; Fig. 3 is a sectional view throu h theeontrol device operated by the fluid fuel; Fig. 4 is a plan view, on a. smaller scale, of the lower portion or half of the-device shown in Fig. 3; Fig. 5 is a top plan view, partly in section, of the upper portion or half of the device shown in Fig. 3; Fig. 6 is a side view partially in. section. similar to Fig. 1 illus-- trating a modification of my invention, and Fig. 7 is a view similar to Fig. 1 illustrating a further modification.

I have illustrated my invention in connection with a steam boiler 10, although it is to be understood thatby invention is not limited to this particular use. The boiler is fired by a furnace, indicated, generally, at 11,provided with a horizontal perforated partition 12 and a combustion chamber 13. The air to the furnace, may be controlled by a dam or 14, which may be operated in anyv desire manner. I have illustrated at 15 a balanced draft device, the construction and operation of which may be the'same as that shown in my Patent No. 1,355,157 October 12, 1920. and need not further be described.

Briefly it maybe stated that the balanceddraft device is operated by urnace pressure and controls the positionof the damper 16 in the outlet flue 17 of theboiler.

I The means for supplying fluid fuel to the furnace comprises a burner or nozzle 18 located preferably in the front ortion of the furnace above the horizonta partition 12. This burner or nozzle may be of any well-known type for feeding fluid fuel ina mixture with an atomizing element, such as steam or air to the furnace chamber. Oil or other fluid fuel is fed to said burner from a pump 19 through a pipe 20, a rate: of-flow device; indicated, generally, at 21 and a pipe 22. A valve member 23 is interposed in the pipe 20, the valve being operated by an arm 24 throu h a cam member 25, which is actuated drum or disc on which is wound a chain 26 passing over a pulley 27 and attached to the piston rod 28 of a device, indicated, generally, at 29, "for controlling the rate, of. feed of the fuel, and here shown as a Mason compensating steam regulator operating in accordance with boiler pressure, and the construction and operation of which is well known to those skilled in the art and need not here. be more full described. It will be understood that the ow of fuel to the furnace may be controlled in any desired manner.

An atomizing fluid, here shown as steam, is supplied to the burner 18 by means of a pipe 30, which is connected to the boiler. A regulating pressure valve 31 is preferably interposed in the pipe 30 for producing substantially constant pressure in the steam supplied to the steam atomizing control valve hereinafter described. The construction and operation of this regulating ressure valve is well understood and use not further be described. V

,In accordance with my invention, the supply of atomizing fluid is controlled by a characteristic "of the flow of fluid fuel to the burner, and referably by the rate of flow thereof. T e rate-of-fiow device 21 by an attached comprises a casing, the lower half of which ber, except as hereinafter described. In-

tegral with the lower half of the casing 32 is an inlet connection 36 having a port 37 leading to an opening 38 through the flange of the member 32 and leading into a assage 39 in the wall of the member 33, said passage 39 commimicating with the space in said member 33 above the diaphragm 35.

The connection 36 is made with that portion of the pipe 20 nearest to and leading from the pump 19. Connected to the lower member 32 is an outlet connection 40 openin into the lower chamber of the regulating evicc below the diaphragm 35, said connection 40 being connected to that part of the pipe 22 leading from the regulator to the burner 18. The chamber in the upper half 33 of the casing above the diaphragm 35 opens through a port 41 into a valve casing 42, preferably formed integral with the member 33 and. containing a tapered turn-plug valve 43, the latter having a port 44 adapted to communicate with the said port 41 and leading to the internal bore 45 of the valve, which, in turn, communicates with a pas sage 46 leading into the chamber beneath the diaphragm 35'. In order to provide for a tight fit, the valve 43 is preferably tapered and fitted to a correspondingly tapered bore in the casing 42 and is forced toward its seat by a spring 47 surrounding a stem 48 of said valve, and at one end abutting a packing gland 49 threaded into the casing 42, and its other end abutting the upper end of said valve 43. The valve is provided with a head 50 adapted to be engaged by a wrench or other suitab e means by which it may be rotated. Connected to the diaphragm 35, in any suitable manner, as at 51, is one end 52 of a rod 53 extending upward through a stuffing box 54 in the upper wall of the member 33, the upper end of said rod 53 being loosely pivoted, as at 55, to a lever 56, one end of which is pivoted, as at 57, to the member 33, and the other end of which is connected to a flexible' member 58, shown as a chain, passing upward over a pulley 59 on a shaft 60, the opposite end of the chain preferably being provided with a counterweight 61. The

means for connecting the rod 53 to the diaphragm preferably consists of a dished plate 62 having a flange 63 secure-d by a fluid tight joint to the lower face of the diaphragm by means of screws 64 extending through said flange, packing washers 65 being interposed between the flange of the dished plate and the diaphragm, the screws being threaded into a washer or ring 66 on.

the upper side of .the diaphragm. The dished portion of the plate 62 extends upward through a central opening in the diaphragm and has a central opening 67 through which the rod 53 extends, the rod haying beneath said plate an enlargement or head 68 of greater diameter than the openin in said plate. The underside of the dis ed plate 62 is closed against leakage by a plate 69 held in place by the screws 64. On the casing of the regulator is abracket 70 between which and the lever 56 is suitably supported and held a compression spring 71 tending to move the lever 56 up-. wardly.

One end of the spring 71 is seated in a spring seat 72 supported on one end of an adjusting screw 73 threaded through the bracket 70 and by means of which the resistanceof the spring 71 to the downward movement of the lever 56 may be regulated.

The screw 73 may be locked in adjusted position by a jam nut 7 4threaded thereon. The upper end of the spring 71 surrounds a lug 75 which is preferably formed on the lower side of the lever arm 56. V

The operation of the rate-of-flow device is as follows: The fluid fuel enters the connection 36 and flows through ports 37 and 39 into the space above the diaphragm 35,

thence through the port 41. and valve port 44 and port or passage 46 into the space beneath the diaphragm 35, from which space it flows outward through the pi )e 22 to the burner 18. The valve 43 is opera dc to cause a restriction to the flow of fluidfuel between the upper and lower chambers of the regulator having a diaphragm between them, so as to create a'reduction in pressure in the chamber beneath the diaphragm, this reduction in pressure being employed to cause movement of the diaphragm in accordance with the rate of flow of fluid fuel to operate the lever 56, so as to control the rate of flow of atomizing fluid in accordance with the rate of flow of fluid fuel, as will be more fully hereinafter described. It will be understood that the valve 43 is set so as to result in a restriction, giving the desired clifference in pressure between the fluid in the two chambers, and any variations in this difference of pressure due to fluctuations in the rate of flow during the operation of the furnace, will operate the diaphragm to correspondingly regulate the position of the arm 56. The chambers on opposite sides of the diaphragm 35 are preferably designed so as to be of equal volume and symmetrical in shape, so that the effect of the velocity head of the fluid flowing through the two chambers will not tend to move the diaphragm, any action of the velocity head on one side of the diaphragm being counterbalanced by a similar action on the other side. The result of the neutralizing or counterbalancing of the pressures in the two chambers is that the diaphragm is actuated by the difference in total pressure due to the restriction of the passage between the two chambers. The movement of the arm 56 through the variations in the rate of flow of fluid fuel through .the regulating device 21 operates the pulley 59 to which is attached a cam member 76 preferably provided with a plurality of radial slots 77, in which are secured bolts 78 progressively removed from the center in the successive slots, so as to form a spiral on which rests an arm 79 weighted as at 80, the arm 79 operating a valve 81 located in the pipe 30 which supplies atomizing fluid to the burn- 1 er, the construction-and operation being such that as the rate of flow of fluid fuel to the furnace increases or decreases, the valve 81 is actuated to correspondingly increase or decrease the supply of atomizing fluid to the 4 burner. It will be understood that the bolts 78 in the slots 77 may be so adjusted that the rate of supply of the atomizing fluid may bear any desired relation to any rate of supply of the fluid to-the burner.

The valve 23 which controls the flow of fluid fuel to the regulating device may be of any suitable form. In'the device illustrated in Fig. 2, the valve member 82 is in the form of a hollow shell and comprises two ilates 82 and 82 connected by guide mem'ers 82 which are received in openings 83 and 83 in a partition member 84, preferably formed integral with the connecting member 85. The valve member 82 is connected by a stem 86 to the inner end of the arm 24, as at 87, the arm being pivoted at 88 in the valve casing. The arm 24 is actuatedby the cam member 25 which may be of the same form as the cam member 76 and need not be more fully descf ibed, it being understood that the cam. member 25 .is actuated by a pulley on which is wound the chain 26.

In the modified arrangement'illustrated in Fig. 6, not only is the supply of atomizing fluid controlled in accordance with a characteristic of the flow of fluid fuel to the burner, but the su ply of air to the furnace is also controlle 1n accordance with a characteristic of the flow of fluid fuel. In the arrangement illustrated the arm 56, which is actuated in accordance with a characteristic of the flow of fluid fuel, and specifically in accordance with the rate .of flow of fluid fuel, actuates not only the valve 81, which controls the supply of atomizing fluid to the burner, but is connected by means of a chain 89, after assing over pulleys 90 and 91 to aweighted' arm 92 on a shaft 93 on WhlCh is mounted a damper 94 in an o 'ening 95 in the wall of the setting, t rough which air is supplied to the space beneath the partition 12 and through the openings in the partition to the furnace. The arm 56, therefore, the movement of which is in accordance with the rate of flow of fluid fuel to the burner, controls not only the supply of atomizing fluid,but contr ols the supply of air to the furnace, so

that the amount of air supplied is in accordance with the amount of fluid supply.

In the arrangement illustrated in Fig.- 7, the arm 56, which controls the supply of atomizing fluid, also -adjusts the position of the balanced draft device 15, the movement of which, in turn, controls the damper 16 in the outlet flue to control the gases passing through'the boiler and furnace. The arm 56 is connected by a chain 96, which passes over pulleys 97 and 98 to an arm on the .lower part of the balanced draft plate in the balanced draft device 15, through a. spring 99. The construction and operation of the spring connection between the chain No. 1,576,754, to which reference may be made for fuller details as to the construction and operation. In the device illustrated in Fig. 7, therefore, not only is the supply of atomizing fluid controlled in accordance with the rate of flow of fluid fuel, but the position of the balanced draft regulator is also adjusted in accordance with the rate of flow offluid fuel, and correspondingly the opening in the outlet flue is varied so that the rate of flow of gases through the boiler and furnace is in accordance with the rate of supply of flhid fuel to the burner.

I claim:

1. The method of operating a furnace for which fluid fuel is atomized by a fluid, which consists in controlling the supply of atomizing fluid in res aonee to variations in the rate of flow of uid fuel to the furnace.

2. The method of operating a furnace for which fluid fuel is atomized by a fluid. which consists in supplying the atomizing fluid at a constant pressure, and controlling the rate of supply thereof to the furnace in accordance with the rate of fuel supply.

3. In a furnace, means for supplying fluid fuel to the furnace, means for atomizing the fluid fuel with a fluid, means for controlling the rate of supply of atomizing fluid in res onse to varlations in the rate of supply of uid fuel. 4. In a furnace, means for supplying fluid fuel to the furnace, means for atomizing the fluid fuel with a fluid, and means for controlling the rate of supply of atomizing fluid in response to variatlons in the rate of 5. In a furnace, means for supplying fluid 11 0 sup lying the atomizing fluid at. a substantial y constant pressure, and means for controlling the rate of supply of atomizing fluid in accordance with the rate of supply of fluid fuel.

7. In a. furnace, means for sup-plying fluid fuel to the furnace, a source of aton-iizing fluid under variable pressure, means for supplying the atomizing fluid at a substantially constant pressure, and means for controlling the nte of su pply of atomizing fluid in accordance with the rate of supply of fluid fuel and means for varying the ratio of the rate of supply of atomizing fluid to the'rate of supply of fluid fuel.

8. In a steam boiler and its furnace, means for supplying fluid fuel to the furnace, means for supplying steam from the boiler for atomiz'ng fluid fuel, and means for controlling the rate of supply of atomizing fluid in response to variations in the rate of supply of fluid fuel.

9. In a steam boiler and its furnace, means for supplying fluid fuel to the furnace, means for supplying steam from the boiler at substantially constant pressure for atomizing the fluid fuel, and means for controlling the rate of supply of atomizing fluid in accordance with the rate of supply of fluid fuel.

10. In afurnace, means for supplying fluid fuel to the furnace, means for supplying air to the furnace, means or atomizing the fluid fuel with afluid, and means for con '1 trolling the rate of supply of atofnizing fluid and of air in response to variations in a cl'iaracteristic of the flow of fluid fuel.

11. In a furnace, means. for supplying fluid fuel to the furnace, means for supplying air to the furnace, means for atomizing the fluid fuel with a fluid, and means for reissue controlling the rate of supply of atomizing fluid and of air in accordance with the rate 'of fuel supply.

. 12. In a furnace, means for supplying fluid fuel to the furnace, an outlet flue pro vided with a damper, a balanced draft device operated in accordance with variations in difference between atmospheric an nace pressures for operating the flue damper, means for atomizing the fluid fuel, and a common means for controlling the rate of supply of atomizing fluid and adjusting the position of said balanced draft directly in response to variations in the rate of cupply of fluid fuel to the furnace' 13. In a furnace, means for supplying fluid fuel to the furnace, an outlet flue provided with a damper, a balanced draft de- Vice operated in accordance with variations in difference between atmospheric and furnace pressures for operating the flue damp,- er, means for atomizing the fluid fuel, and a common means for controlling the rate of supply of atomizing fluid and adjusting the position of said'balanced draft device to maintain a fixed relation between the rate of supply of fluid fuel of the furnace and the rate of supply of air to the furnace.

EMBURY MCLEAN. 

